Did You Know: The Hawaiian Alphabet has 12 Letters?
Officially the written form of Hawaiian has 13 letters (a,e,i,o,u,h,k,l,m,n,p,w, and (‘) the ‘okina). The ‘okina is a glottal stop and is considered a consonant; without it the meaning of a word is changed (ie “ko’u”, meaning “my” and “kou” meaning yours)
Some instructors will tell you that there are in fact 10 vowels (a,e,i,o,u,ā,ē,ī,ō,ū).
Spoken Hawaiian on the other hand also has the letters t,r,v, b, and y sounds. The letters t/k, r/l, v/w, and b/p are interchangeable. Because some individuals pronounce “Hawai’i” as “Havai’i”, or “kūkū” instead of “tūtū”, when creating a written form, one of the two interchangeable letters from each pair had to be omitted. The “y” sound is written as “iā”. Written Hawaiian and spoken Hawaiian don’t always go hand in hand.